# poiss.samp: Estimates sample sizes for desired power using simulation... In RSPS: RNA-Seq Power Simulation

## Description

The function provides estimate of sample size for given power when there is over-dispersion. The data is simulated from Poisson distribution.

## Usage

 `1` ```poiss.samp(power, lambda1, k, alpha, seed, numsim, sig) ```

## Arguments

 `power` A vector of values between 0 and 1 representing desired power. `lambda1` Mean count under the null distribution. It can be a vector. `k` Fold change desired under the alternative distribution. It can be a vector. `alpha` Type I error rate: a value between 0 and 1. It can be a vector. `seed` Value of seed to ensure reproducibility of results. `numsim` Number of simulations. 1000 is recommended. `sig` Number of significant digits after decimal.

## Details

The test statistic used is the scaled difference. Please contact the authors for more details on algorithm.

## Value

 ` Power.Expected ` Desired Power. ` Mean.Null ` Mean Count under Null distribution. ` Effect.Size ` Fold Change Under the alternate hypothesis. ` N.est ` Estimated sample size. ` Power.est ` Estimated Power. ` Std.Err ` Standard Error.

None

Milan Bimali

None

rpois

## Examples

 ```1 2 3 4 5 6 7 8 9``` ```power = c(0.7,0.8);lambda1=3;k=seq(2,3,0.5); alpha=0.01;seed = 20;numsim=100 sample.poiss <- poiss.samp(power,lambda1,k,alpha,seed,numsim) sample.poiss # Another example (takes longer to run) #power = seq(0.7,0.9,0.05);lambda1=3;k=seq(2,3,0.5); #alpha=0.005;seed = 20;numsim=1000 #sample.poiss <- poiss.samp(power,lambda1,k,alpha,seed,numsim) #sample.poiss ```

### Example output

```  Power.Expected Mean.Null Effect.Size Type.I.Error N.est Power.est Std.Err
1            0.7         3         2.0         0.01     8      0.79   0.041
2            0.8         3         2.0         0.01    10      0.93   0.026
3            0.7         3         2.5         0.01     5      0.82   0.038
4            0.8         3         2.5         0.01     5      0.82   0.038
5            0.7         3         3.0         0.01     3      0.81   0.039
6            0.8         3         3.0         0.01     3      0.81   0.039
```

RSPS documentation built on May 29, 2017, 1:18 p.m.